A machine with a cost of $180,000 has an estimated residual value of $20,000 and an estimated life of 5 years or 20,000 hours. It is to be depreciated by the units-of. activity method. What is the amount of depreciation for the second full year, during which the machine was used 6,900 hours? b. 535,260 c. 555,200 d. 569,000